A study is currently underway in Merced, Madera, Tulare and Fresno counties to examine the pros and cons of building groundwater recharge basins near rural communities.

The two-year study is a continuation of an earlier Feasibility study focuses exclusively on Fresno County and both are led by the California Water Institute at Fresno State University.

““Floodplains and groundwater recharge know no geographic boundaries,” Laura Ramos, interim director of the institute, wrote in an email. “Sometimes the best recharge area for Madera County is in Merced County, so it was important for us to look at a larger geographic area.”

Key to this regional study is the use of surface water channeled through the Friant-Kern and Madera canals. Researchers hope to find the best sites for groundwater recharge near disadvantaged communities whose residents often face lower groundwater tables due to over-extraction of agricultural land. This often results in poor water quality or, worse, no water at all because community wells are not deep enough.

Institute staff, as well as university faculty and students, will work with the Tulare Irrigation District, North Kings Groundwater Sustainability Agency, Madera County and the nonprofit Self-Help Enterprises to improve water quality and access for residents who rely on shallow domestic wells or small water systems.

The $500,000 study is funded by the state Office of Planning and Research, which promotes collaboration between state and local partners in land use, planning and economic development. Ramos said the original plans called for including Kings and Kern counties, but limited funding narrowed the focus. The institute hopes to study those counties in the future.

Ramos said leveraging the strengths of other organizations will lead to better projects for San Joaquin Valley residents.

For example, the Institute will use a data system that serves as FREEor Groundwater Recharge Assessment Tool, developed by Sustainable Conservation, which helps irrigation districts and groundwater authorities create recharge scenarios. The tool allows water managers to assess where, when and how much water can be recharged based on the best available hydrological, agronomic and geological evidence over a 20-year period. Importantly, the tool also brings to light unintended environmental and social impacts.

Here too, Self-Help Enterprises’ experience and relationships in local communities come into play.

“There will be groundwater recharge basins throughout the San Joaquin Valley,” Ramos said. “Residents in disadvantaged communities may not know what they are, how they can benefit from them, or what concerns they should have.”

Sue Ruiz, education coordinator at Self-Help Enterprises, pointed to the newly inaugurated Okieville Supply Basin near Tulare as an example of a project that is helping a downslope community reduce groundwater nitrate levels while raising the water table for shallow wells.

However, she advocates for more data collection.

“When we play with sand and water, we have to think about how particles move,” she said. “We think they’re beneficial for communities with nitrate problems, but if the water flows between a basin and a community that used to have a dairy, is that going to push nitrate into the water system further downstream?”

She also urged researchers to think long-term: Once a pool is built, who will be responsible for its maintenance and how will it be financed, she asked.

“The operation and maintenance of the pools needs to be carefully analyzed,” she said. “Those are the questions Self-Help will raise, to get the community’s perspective on all of these things so that we don’t face unintended consequences. We need to think ahead and be a little pessimistic.”

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